1. Field of the Invention
The present invention relates generally to a temperature control fixture for an integrated circuit (IC) Device Under Test (DUT), and more particularly pertains to a temperature control fixture which provides for cooling or heating of one side of an integrated circuit which is being tested by contacts and electrical leads applied to the opposite side thereof.
2. Discussion of the Prior Art
Prior art test fixtures for integrated circuits have not provided for suitable testing of an integrated circuit which must be cooled or heated from the same side as it is being viewed during testing.
Moreover, such prior art test fixtures have not adequately controlled thermal expansion gradients which can cause fracturing of thinned, active integrated circuits. This problem arises when active, power dissipating devices are nonuniformly distributed on the integrated circuit and the structural strength of the integrated circuit is reduced due to thinning.
Other problems arise from heating of the viewing optics and camera by thermal infrared (IR) radiation, which can cause camera noise and possible damage to the integrated circuit.
The present invention provides a solution to a problem which arises when an integrated circuit must be heated or cooled from the same side as it is being viewed during testing.
The problem confronting the present invention is that for testing purposes, one would like to apply test signals to an integrated circuit silicon chip from the electrical lead side thereof while observing the opposite side of the silicon chip. During such testing; any defects in the integrated circuit silicon chip, such as shorts in the silicon gate areas, are likely to emit radiation in the near infrared portion of the spectrum (generally from 0.7 to 0.5 microns). The defects provide mechanisms similar to those in an LED (Light Emitting Diode) to generate and emit such radiation in the near infrared portion of the spectrum.
This testing requires the application of test signals to the electrical leads in the lead side of the integrated circuit silicon ship under normal application, heat stabilized conditions. However, under normal heat stabilized conditions the opposite side of the integrated circuit silicon chip is in contact with a heat sink to enable the chip to function in a normal thermally stabilized manner.
To observe the opposite side of the integrated circuit silicon chip requires removal of the normal heat sink applied thereto.